Young and middle-aged Americans are experiencing a sharp rise in hospitalization for strokes, says a new study echoing Canadian research that this age group is at greater risk for heart disease than they were in the past.

The U.S. numbers, reported Wednesday at an American Stroke Association conference in California, come from the first large U.S. -wide study of stroke hospitalizations broken down by age. Government researchers compared figures in 1994 and 1995 with those in 2006 and 2007.

The U.S. Centers for Disease Control and Prevention number show the sharpest increase - 51 per cent - was among men under the age of 35. Strokes rose among women in this age group, too, but not as fast -17 per cent.

The Canadian Heart and Stroke Foundation's 2010 annual report describes a similar problem in this country. It showed that between 1994 and 2005, rates of high blood pressure among Canadians in general skyrocketed by 77 per cent, while diabetes rose by 45 per cent and obesity by 18 per cent.

It also said that more than 250,000 Canadians in their 20s and 30s had high blood pressure, making them the newest at-risk group.

High blood pressure, diabetes and obesity increase a person's likelihood of suffering a stroke.

The problem was worst among those aged 35 to 49. The prevalence of high blood pressure in that age group increased 127 per cent, diabetes by 64 per cent and obesity by 20 per cent.

The Heart and Stroke Foundation blamed unhealthy eating habits and lack of exercise for the problem.

Meanwhile, the CDC study showed the trend went the opposite way in older people. Hospitalization from strokes dropped by 25 per cent among men 65 and older and by 28 per cent among women in this age group.

Doctors think better prevention and treatment of conditions such as high blood pressure in older people may be contributing to the decline.

With files from The Associated Press